Enhanced spin-orbit coupling and charge carrier density suppression in LaAl1-xCrxO3/SrTiO3 hetero-interfaces

Pramod Kumar, Anjana Dogra, P. P.S. Bhadauria, Anurag Gupta, K. K. Maurya, R. C. Budhani

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

We report a gradual suppression of the two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 interface on substitution of chromium at the Al sites. The sheet carrier density at the interface (n) drops monotonically from ∼2.2 × 1014 cm-2 to ∼2.5 × 1013 cm-2 on replacing ≈60% of the Al sites by Cr and the sheet resistance (R) exceeds the quantum limit for localization (h/2e2) in the concentrating range 40-60% of Cr. The samples with Cr ≤40% show a distinct minimum (Tm) in metallic R(T) whose position shifts to higher temperatures on increasing the substitution. Distinct signatures of Rashba spin-orbit interaction (SOI) induced magnetoresistance (MR) are seen in R measured in out of plane field (H) geometry at T ≤ 8 K. Analysis of these data in the framework of Maekawa-Fukuyama theory allows extraction of the SOI critical field (HSO) and time scale (τSO) whose evolution with Cr concentration is similar as with the increasing negative gate voltage in LAO/STO interface. The MR in the temperature range 8 K ≤ T ≤ Tm is quadratic in the field with a +ve sign for H and -ve sign for H. The behaviour of H MR is consistent with Kondo theory which in the present case is renormalized by the strong Rashba SOI at T < 8 K.

Original languageEnglish
Article number125007
JournalJournal of Physics Condensed Matter
Volume27
Issue number12
DOIs
StatePublished - 1 Apr 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015 IOP Publishing Ltd.

Funding

FundersFunder number
Council of Scientific and Industrial Research

    Keywords

    • 2DEG
    • magnetoresistance
    • oxide hetero-structures

    Fingerprint

    Dive into the research topics of 'Enhanced spin-orbit coupling and charge carrier density suppression in LaAl1-xCrxO3/SrTiO3 hetero-interfaces'. Together they form a unique fingerprint.

    Cite this